Entwine or interlace (tree branches) to form a hedge or provide cover for an outdoor walkway.
Late Middle English: from an Old French variant of plaissier (see plash).
“He created the pleach walkway to the house over many years.”
With regard to, or at the level of, orders in a taxonomic system; according to an ordinal number, system, etc.; on an ordinal scale; with regard to order.
Mid 19th century; earliest use found in The Edinburgh Review. From ordinal + -ly.